Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 986,918	$ 1,007,981	$ 1,040,873
Cost of sales	750,374	763,219	853,897
Gross profit	236,544	244,762	186,976
Selling, general, and administrative expense	143,448	161,099	133,381
Intangible asset impairment	247	10,175	4,863
Income from operations	92,849	73,488	48,732
Interest expense	14,032	14,577	15,003
Other expense (income)	909	8,928	(3,371)
Income before taxes	77,908	49,983	37,100
Provision for income taxes	14,943	16,264	13,624
Income from continuing operations	62,965	33,719	23,476
Discontinued operations:
Loss before taxes	(644)	(70)	(44)
Benefit of income taxes	(239)	(26)	(16)
Loss from discontinued operations	(405)	(44)	(28)
Net income	$ 62,560	$ 33,675	$ 23,448
Net earnings per share – Basic:
(Loss) income from continuing operations (in dollars per share)	$ 1.98	$ 1.07	$ 0.75
Loss from discontinued operations (in dollars per share)	(0.01)	0.00	0.00
Net (loss) income (in dollars per share)	$ 1.97	$ 1.07	$ 0.75
Weighted average shares outstanding – Basic (in shares)	31,701	31,536	31,233
Net earnings per share – Diluted:
Income (Loss) from Continuing Operations, Per Diluted Share	$ 1.95	$ 1.05	$ 0.74
Loss from discontinued operations (in dollars per share)	(0.01)	0.00	0.00
Net (loss) income (in dollars per share)	$ 1.94	$ 1.05	$ 0.74
Weighted average shares outstanding – Diluted (in shares)	32,250	32,069	31,545